Thermoplastic copolyetherester elastomers, such as those disclosed in U.S. Pat. No. 3,766,146, are known for their generally good physical properties and their outstanding processing characteristics. Unfortunately, these copolyetheresters are deficient in scuff resistance which reduces their suitability in certain applications. Moreover, lower hardness grades of copolyetheresters lack toughness; for instance, their tensile and tear strengths are often lower than desired.
A unique class of copolyetherester elastomers containing imide-diacid segments and polyether segments has been found. The polymers are thermoplastic elastomers which have improved scuff resistance and excellent stress-strain properties even at low hardnesses.